From: "H. Peter Anvin" <hpa@zytor.com>
To: Matteo Croce <matteo@openwrt.org>
Cc: Thomas Backlund <tmb@mandriva.org>,
linux-kernel@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>,
Natale Vinto <ebballon@gmail.com>
Subject: Re: AMD Geode NOPL emulation for kernel 2.6.36-rc2
Date: Fri, 27 Aug 2010 16:07:48 -0700 [thread overview]
Message-ID: <4C784544.2010305@zytor.com> (raw)
In-Reply-To: <AANLkTinjHK-oTmt-6cmN16jWWv9ZjW44wA-A3VTLm+A_@mail.gmail.com>
On 08/27/2010 02:32 PM, Matteo Croce wrote:
> can I ignore the return value when I expect val to be non zero?
> the doc says: "On error, the variable @x is set to zero."
No. You need to deliver a page fault to the application in this case.
The *real* test for this kind of crap is correct page fault behavior,
and so forth.
Also, at the very least you need to check for:
- CS == USER_CS
- IP in the proper range for user space
Your patch in its current form is one big security hole.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2010-08-27 23:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-27 18:07 AMD Geode NOPL emulation for kernel 2.6.36-rc2 Matteo Croce
2010-08-27 18:48 ` H. Peter Anvin
2010-08-27 20:15 ` Matteo Croce
2010-08-27 20:49 ` Thomas Backlund
2010-08-27 21:32 ` Matteo Croce
2010-08-27 22:16 ` Matteo Croce
2010-08-27 22:19 ` Matteo Croce
2010-08-27 23:07 ` H. Peter Anvin [this message]
2010-08-29 12:52 ` Avi Kivity
2010-08-29 13:39 ` Matteo Croce
2010-09-08 20:59 ` H. Peter Anvin
2010-08-27 20:54 ` H. Peter Anvin
[not found] <fmbxh-5N8-41@gated-at.bofh.it>
2010-09-07 15:57 ` Nick Lowe
2010-09-08 9:15 ` Hans-Peter Jansen
2010-09-08 11:34 ` Nick Lowe
2010-09-08 11:55 ` Nick Lowe
2010-09-08 17:56 ` Alan Cox
2010-09-08 17:51 ` Nick Lowe
2010-09-08 19:07 ` Alan Cox
2010-09-08 19:44 ` Nick Lowe
2010-09-08 21:11 ` Alan Cox
2010-09-08 21:05 ` H. Peter Anvin
2010-09-08 21:07 ` Nick Lowe
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